Everyone knows that MARIAH CAREY and NICKI MINAJ were beefing during the "American Idol" audition rounds . . . so it's no surprise to hear that the show's producer, NIGEL LYTHGOE, would like you to believe KEITH URBAN is also acting ornery.--Lythgoe told some TV critics at a press event that Keith and fellow judge RANDY JACKSON have had their share of fights.  Keith was there too and he agreed, adding, quote, "We have gone at it."

--And then in a separate interview Lythgoe took it even further. --He said, quote, "When it's (Keith's) turn to speak, he gives his mind and he won't put up with anybody else knocking a kid down.  He's had rows with both Mariah, Randy and Nicki . . . a big one with Nicki."

(--Keith also did an unrelated interview with "Access Hollywood" where he talked about his experience on the show so far.  Here's the video.)